/**
 * @param {string} astr
 * @return {boolean}
*/
var isUnique = function(astr) {
  let set = new Set([...astr.split("")]);
  return set.size == astr.length;
};
let s = "leetcode";
console.log(isUnique(s));
s = "abc";
console.log(isUnique(s));
